1. Field of the Invention
The present invention relates to a multichip module in which a plurality of semiconductor chips such as ICs (Integrated Circuits) and LSI (Large Scale Integration) devices are disposed in a single package, more specifically to a multichip module provided with a temperature control function against overheating.
2. Related Art
In recent years, an increasing density of electronic circuits including computers and peripheral equipment, mobile equipment such as cellular phones, onboard equipment such as car navigation systems, etc. has been accomplished and there is strong demand for downsizing, higher integration and larger capacity of IC and LSI packages. On the other hand, there is strong expectation for a system LSI in which a system comprising a plurality of ICs and/or LSI devices is fabricated on a single chip (i.e., a single silicon substrate). However, designing on a single chip increases development cost and time and also requires large investments and the like for increasing integration. In order to provide a single LSI, a so-called multichip module technology in which a plurality of semiconductor chips are mounted on and sealed in a single package has been attracting attention in recent years, as an approach from packaging technologies.
As compared to a conventional interconnect of a plurality of semiconductor chips on a printed circuit board on which discrete components such as resistors, capacitors and the like are mounted on a relatively wide area, the multichip module technology is effective to decrease total length of interconnect patterns, downsize and also improve noise performance including reduced EMI (Electro Magnetic Interference). Also, in addition to the capability of installing existing LSI devices without any modification and thus maintaining essentially the same reliability as conventional packages, it is possible to significantly reduce the time required for the development. Moreover, it is possible to install modules of different fabrication processes in various combinations, thereby providing more versatile and yet less expensive semiconductor devices.